Add Shan (shn) to clean_sandbox.py
Add Shan (shn) to clean_sandbox.py

Bug: T210047
Change-Id: I6a4f773d58e5cc4c24d6a6d9403af3bde8304e93

wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core